Browsing by Author "Kelton, David F."

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    Disease Control on Dairy Farms with a Focus on Johne's Disease and Veterinary Communication
    (2018-04-19) Ritter, Caroline Manuela Nancy; Barkema, Herman W.; Adams, Cindy L.; Jansen, Jolanda; De Buck, Jeroen M.; Kelton, David F.; Mason, Steve
    Motivating dairy farmers to implement disease prevention and control strategies can be challenging. The first objective of this thesis was to assess factors that influence farmers’ management decisions. A literature review was conducted focusing on socio-psychological influences and farmers’ preferred information sources. Additionally, surveys and qualitative interviews with Alberta dairy farmers contributed to the current knowledge by assessing farmers’ attitudes, beliefs, and perceptions in regard to the prevention and control of Johne’s disease, an infectious enteritis that is caused by Mycobacterium avium subsp. paratuberculosis (MAP) and is endemic in Canadian dairy cows. Environmental fecal samples were analyzed for MAP to assess whether farm infection status influenced farmers’ decision to enroll in the voluntary Alberta Johne’s Disease Initiative (AJDI). Observed herd prevalence of MAP (i.e., 51%) was similar between AJDI participants and nonparticipants. Results further indicated that farmers have to believe in the importance of the disease and in recommended prevention and control strategies to make changes. In Alberta, the reasons why farmers did not participate in the AJDI or implemented recommended measures included skepticism of the threat and negative effects of Johne’s disease, critique of test sensitivity, required time, and costs. Farmers used a variety of information channels, but herd veterinarians had a major influence on their management. Veterinarians are in an ideal position to communicate and motivate recommended strategies targeted to each farm, and it is well established that effective communication skills can improve adherence with advice and health outcomes. Therefore, the second objective was to assess veterinary communication patterns. First, the suitability of on-farm video recordings for comprehensive communication analysis using the Roter Interaction Analysis System was demonstrated. Then, veterinary communication during 70 dairy farm visits was assessed. Veterinarians spent most of their talk on farmer education and relationship building. Demographics such as gender and length of the professional veterinarian-farmer relationship affected the use of some communication variables, whereas the effect of previous communication training was minimal. Identification of influences on farmers’ management decisions and of veterinary communication patterns can reveal opportunities to enhance communication, thus improving the uptake of prevention and control measures.
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    Longevity in Canadian Dairy Cows
    (2020-01-15) Schuster, Jessica Claire; Orsel, Karin; Barkema, Herman W.; Kelton, David F.
    A thorough review of longevity in dairy cows was conducted to evaluate current understanding of longevity. Current terminology referring to longevity is inconsistent; therefore, standardized definitions are needed. Longevity is affected by genetics, environment and management impacts, along with culling decisions for genetic improvement. Therefore, this thesis proposes that producers aim to optimize longevity by ensuring a favourable environment via optimal management, providing each cow an opportunity to reach her full genetic potential. An evaluation of animal-level variables was conducted to identify intrinsic factors affecting longevity. Additionally, an economic evaluation that assessed individual impact of each of these variables on lifetime profitability was estimated. Reproductive performance had the greatest impact on estimated culling time and profitability in young-stock and cows, suggesting performance indicators (e.g. milk production, reproduction, health and young-stock performance) should be incorporated into farm level evaluations of longevity to enable producers to make evidence-based decisions for optimizing longevity.